ISCHEMIC DETERIORATION FOLLOWING ANEURYSMAL SUBARACHNOID HEMORRHAGE -DEFINITION BY CLINICAL-CRITERIA

Ischaemia following surgery for aneurysmal subarachnoid haemorrhage (S AH) was defined by clinical criteria. Two distinct groups of patient d eveloping ischaemia were identified: (1) patients recovering from anae sthesia with a new deficit or (2) patients developing 'true' delayed i schaemia. The only significant difference between the groups was an ex cess of pre-existing vascular disease in the former group. The eventua l outcome for patients developing an immediate postoperative deficit w as not significantly different from the delayed ischaemia group. The 6 -month outcome for patients without clinical ischaemia in the first 10 postoperative days was excellent. The potentially different aetiology of ischaemia in the two subgroups with clinical ischaemia identified in this study should be considered during the planning and in particul ar the statistical design of trials testing new treatments for clinica l ischaemia following aneurysmal SAH.